一个勘探区或井田所进行的煤田地质工作,由于其范围不大,而地层单位划分较细,在作精确的地层对比过程中,把时代延续较长的古生物加以进一步的研究作为地层对比的依据,往往容易被忽视。本文述及的海豆芽(Lingula)化石,由于它延续时间 Because of its small area and fine stratigraphic uniting, coalfield geology work in an exploration area or well field is further studied as a basis for stratigraphic correlation during the precise stratigraphic comparisons , Tend to be easily overlooked. The Lingula fossils mentioned in this article are due to its duration